On-canvas calculations within Power BI enable analysts to perform computations directly within a visual element without altering the underlying data model. As an example, one can calculate a running total directly on a bar chart to view cumulative sales figures over time. These computations exist solely within the context of the particular visual in which they are defined.
This functionality enhances data exploration and reporting flexibility, allowing for rapid prototyping of analytical insights. Prior to the introduction of this feature, users were often required to modify the data model or create calculated columns to achieve similar results. This could be time-consuming and potentially impact the overall performance of the report. The direct visual calculation empowers analysts to derive value from their data more rapidly and efficiently.